Reading Notes for Chapter 01


These are Dr. Bodwin's reading notes for Chapter 01 of "Chemistry 2e" from OpenStax. I am using a local .pdf copy that was downloaded in May 2020.

Chapter Summary:

What exactly is "chemistry"? This chapter aims to set the table for our semester or year of studying chemistry. People often treat first chapters as throw-away material, but it is important to take this chapter seriously to get familiar with the format and style of the book as well as the most fundamental tools we will use in our study.

What is "chemistry":

One of my favorite college professors defined chemistry as "stuff changes into other stuff".
Chemistry is the study of matter and its changes.
I often find it helpful to think about different science disciplines in terms of how they balance theory and application. Chemistry tends to be a little less theoretical than physics, and a little more theoretical than biology or engineering. That's not an absolute truth, and it doesn't make any of those fields better or worse, it's just a way to frame our approach.

Nature of Science/Scientific Approach/Scientific Method:

The key to all science is curiosity. Whenever you see something happening, it should be pretty natural to wonder "Why?"
The way I think about the "scientific method" is something like this... and I'll tell it like a story:
The other day, I did a thing. When I saw what happened, I thought, "Huh, that's weird. I wonder why it did that? Maybe it did that because of this." So I did the thing again to see what would happen the next time. And it did the same thing. I tried it a few more times just to be sure, but it looks like my explanation might make sense. My friend tried to do the same thing, and she saw the same thing happen. We asked a lot of other people, and it looks like every time some does that thing, they see the same thing happen. A bunch of the other people thought my explanation made sense and when they did the thing it seemed to match my explanation, so we're pretty sure we're right, but we should probably continue to check out what happens when we do the thing and adjust our explanation if we need to.
Translating that into "science" words...
The other day, I did a thing. (Observation) When I saw what happened, I thought, "Huh, that's weird. I wonder why it did that? Maybe it did that because of this." (Hypothesis) So I did the thing again to see what would happen the next time. (Experiment) And it did the same thing. I tried it a few more times just to be sure (Repeat Experiments, Make Predictions), but it looks like my explanation might make sense. My friend tried to do the same thing, and she saw the same thing happen. We asked a lot of other people, and it looks like every time some does that thing, they see the same thing happen. (Law) A bunch of the other people thought my explanation made sense and when they did the thing it seemed to match my explanation, so we're pretty sure we're right, but we should probably continue to check out what happens when we do the thing and adjust our explanation if we need to. (Theory)  

States of Matter:

States of matter is actually a topic we will re-visit a number of times throughout the course. Depending what we are trying to explain, we will need definitions of different precision or focus. The "how matter interacts with its container" definitions are a good place for us to start.
"Matter" is something that has mass and occupies space.
Pay attention to the distinction between "mass" and "weight". Mass measures the amount of a substance; weight measures how matter is affected by gravity and its medium.
The Law of Conservation of Matter can be stated a few different ways (just like the definitions of the states of matter). Probably the most basic ways is "matter cannot be created or destroyed". We'll look at a few cases where that simple definition isn't exactly true, but it's a good place to start.
One of the best ways to figure out the distinction between elements, compounds, and mixtures is to just observe things around you. Look for examples and test your examples. You're a scientist, afterall.

Physical and Chemical Properties and Changes:

Why are we studying "physical" changes in a chemistry course?
Extensive vs Intensive properties are important... What weighs more: a kilogram of lead or a kilogram of feathers?
The NFPA hazard diamond appears in a LOT of places. Once you start looking for it, you'll see it. To help remember what which part means what, these are sometimes called "heifer diamonds" because the top 3 squares are "H-F-R" for "health", "fire", and "reactivity".

Measurements and Math:

There are a lot of different things we can measure. I will typically give you conversion factors, but there are some that I will expect you to be able to do without a conversion factor, most notably metric/SI prefix conversions. You shouldn't need to write out a big, complex mathematical equation to convert milliliters to liters or meters to centimeters... practice these and they will become much easier to work through.
Accuracy and precision are BOTH important. Accuracy can often be improved with practice, precision is usually improved with changes to an experiment.
Significant Figures (sigfigs) are important because they give us information about the uncertainty of a number. They take practice. But remember, sigfigs are not just some meaningless thing that chemistry professors obsess over, they are important because they tell us how reliable a measurement is. Sig Figs Slides
I will be evaluating sigfigs in any numerical answers you provide in your assignments for this class.
I am a HUGE proponent of dimensional analysis. If you pay attention to units on every number you use, you will make FAR fewer errors, and you will even be able to do some problems that you've never seen before just by following the dimensional analysis.
"Conversion factors" are just relationships between 2 different descriptions of the same quantity. Use dimensional analysis to figure out how use them.
Temperature conversions are excellent examples of learning a process rather than just memorizing a formula. The book derives formulas, but make sure you look at the process being used.


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